U.S. Pat. No. 7,758,642, which is incorporated herein in its entirety by reference, discloses the use of a perforated sheet to assist in implant fixation. U.S. Pat. No. 5,984,926, issued on Nov. 16, 1999, which is incorporated herein in its entirety by reference, discloses a suture based device for saving screw holes in bone, as well as various problems associated with achieving adequate grip or achieving adequate bone screw purchase strength in cancellous bone or osteopenic/osteoporotic bone or bone where the fractures or poor quality bone preclude optimal engagement of bone.
Because of the variety of types of injuries, bone conditions and anatomical variations and limitations, there remains a need for devices that improve screw purchase strength in a variety of clinical situations. Known methods, such as the method described in U.S. Pat. No. 8,163,031 to Truckai et al., incorporated herein in its entirety by reference, discloses a sleeve for improving the grip of the screw with the bone. However, the Truckai et al. device does not allow the surgeon to adjust the thickness of the insert. Also, a significant problem associated with pedicle screws is that they often move within the screw hole, and the sharp point of the screw causes damage to the bone around the tip, as well as causes pain to the patient due to the close proximity of the screw tip and nerves or other sensitive tissue.
Still further, the device disclosed in U.S. Pat. No. 5,984,926 may be inserted using a rod, and thus the device would benefit from the use of an insert that would assist the surgeon in engaging and centering the sleeve while pushing the sleeve into the screw hole.